Arresting unit for aircraft landing system



Aug. 31, 1948- r. M. BOYER ETAL I 2,448,209 v I ARRESTING UNIT FOR AIRCRAFT LANDING SYSTEM 7 4 Sheets-Sheet 1 Filed 'Jan. 23, 1946 INVENTOR. TAYLOR MB OYER AND BY CLARENCE RGOTTSCHALL Aug. 31, 1948.

4 Sheets-Sheet 2 Filed Jan. 23, 1946 WW mm INVENTOR. TAYLOR MBOYE-R AND BY CLARENCE RGOTTSCHALL THEIR 4 T TOZ/VE Y.

Aug. 31, 1948. T. M. BOYER EI'AL 2,448,209

ARRESTING UNIT FOR AIRCRAFT LANDING SYSTEM Filed Jan. 23. 1946 v I 4 Sheets-Sheet 5' INVEN TOR.

TAYLOR MB OYE R AND BY CLARENCE R. 6 0T TSOIIAL L Aug. 31, 1948. T. M. BOYER ETAL 2,448,209

ARRESTING UNIT FOR AIRCRAFT LANDING SYSTEM Filed Jan. '23, 1946 4 Sheets-Sheet 4 y CLARENCE RBOTTSCHALL 7/4572 ATTOZNE-Y- Patented Aug. 31, 1948 ARRESTING UNIT FOR AIRCRAFT LANDING SYSTEM? Taylor M. Boyer and Clarence .R-. Gottschall, Wilmington, Del., assignors toAll American ,Avlation, 1110., Wilmington, Del.,. a corporation of Delaware Application January 23, 1946, Serial No. 642,808

(01. zoo-110) 6 Claims.

This invention relates to aircraft landin systerns and is concerned primarily with the arresting unit which is includedin such asystem as an essential element thereof.

With the advent of the world war there has comeinto use certain apparatus employed for the purpose-of landing aircraft. This apparatus is commonly known as a Brodie system and comprises generally a trolley to which an aircraft which isto be landed is adapted to be attached. This trolley moves over a guide line and connected thereto is a line which is taken up on. an energyabsorbing winch. This winch is commonly known as the arresting unit. It is with such an arresting unit that this invention is primarily concerned.

Inproviding an arresting unit for aircraft landing systems of the type above noted, certain factors assume importance. In the first place, the device must operate with a degree of certainty which will eliminate any possibility of its failing to. function at thetime and in the manner intended, In viewlof this requirement the invention has. as an, object the provision of an arresting unitof the character above noted which includes hydraulic braking instrumentalities for retarding rotation-of the drum.

An aircraft landing system, of the type with which this. invention is concerned requires that the aircraft be brought to a stop within a certain predetermined distance. This means that various aircraft. must be landed with a high degree of uniformity To the end of achievin this uniiormity the invention has as a further object the provision of an arresting unit including hydraulic braking instrumentalities which are adjustable to provide foran accurate setting of the hydraulic pressure which will be applied to the braking means; thus, aircraft of various sizes and different. landing speeds may be accommodated due to this adjustability.

When. a landin aircraft first engages the trolley, it has a fairly high velocity. This means that the drumof the winch must be quickly accelerated to a high speed of rotation in a very brief interval. It is enough that the momentum of inertia of the drum be overcome to achieve this rapid acceleration without having any braking resistance which also must be overcome.

determined interval which must elapse after the drum is started in rotation: beforetheibrakes. are applied.

Various other more. detailed objects-and advantages of the invention such as arise in connection withthe. carrying out of. the. above'notedthoughts in a practical embodiment will in: part become apparent and inpart: be hereinafter: stated asthe description. of. the, invention proceeds;

The invention, therefore, comprises aniarresting unit for aircraitlanding systems andwhich unit consists of a winch,hydraulicibraklng. in,- strumentalities associated; with the winch. and including means for;adjusting-thehydraulidpres, sure-thereof together, with time delay mechanism; for controlling thev momentum-.701 initiation of brake application.

. For a. .full and. morezcomplete:understanding;of the invention, reference may; be hadat'o: the fol;- lowing descriptions, andcaccompanying drawingswherein Figure 1 is {a perspective: view, somewhatv die. grammatic, of an aircraft landing:;system;of: the type with which this; invention. is concerned;

Figure 2 is a transverse. section-through; the arresting. unit.

Figure 3 isan enlarged; detailed view in; side; elevation developingcertainparts of the time delay mechanism.

Figure 4 is a perspective view of, thedrumand associated-g hydraulic braking instrumentalities; shown as; removed from: the remainder; of" the structureand Figure. 5- isran end elevattonzof:thegunits.

Referring now, to the 1 drawings. wherein like:

- reference characters denote. corresponding, parts understood; that the uprights; l 0; and; It may be 1 mounted on any appropriatersurfacesuch'asthe:

deckpof, a'shipor on alandi ng:field.- Extending; outwardly ifromythe. upright; I01; and: substantially, normal theretois -a-.horizontal3bar:l 3 while asim'w ilar horizontal. bar It extends outwardlyr froma the, upright I I Extending :betweem their outer nds ofthebars l3gandllis aguideline l'5e-on'x which is: suspended a trolley; whichyis: designateda A contact 100p I1 is shown as yieldablyheldvin;

position; in a-irame. [8. by; clips; [9.4, The frame-.1 8

is carried; by the outer, end of :theibalrjl 3. Thisr. contact loonisconnected tcthestrollemlc by the:

c nnei n s qwnat:20s

An arresting unit is referred to in its entirety by the reference character U and this unit may be located in any suitable position adjacent to the upright if A line 2i preferably of nylon or equivalent synthetic plastic fibers extends from the unit U over sheaves 22 and 23 to the trolley l6.

An aircraft which is to be brought to a stop by the landing system above described is indicated at A, The aircraft A carries an upwardly extendin arm 24 on the free end of which is a hook 25 that is adapted to engage the contact loop l1.

Referring now more particularly to Figures 2 to inclusive, the unit U is shown as comprising a casing structure which encloses the winch mechanism and which provides side frames 26 which constitute the supporting structure for the winch mechanism,

Referring now more particularly to Figures 2 and 4, a drum 21' is shown as carried by a shaft 28 which is journaled in the side frames 26. The drum 2'! includes side flanges 29 which together with the outer cylindrical surface of the drum define the space in which the line 2| is accommodated.

A brake drum 3% is anchored to each of the side flanges 29 in any preferred manner such as by the fastening elements shown at 3!. There is a brake drum to at each end of the drum 21 and these drums 36 may take the form of the ordinary automotive brake which offers an inner cylindrical braking surface 32. Cooperating with this braking surface 32 are a pair of brake shoes 33 which are pivotally anchored to the side frames as shown at 34. The upper ends of the brake shoes 33 are operatively connected to a hydraulic actuating mechanism 35.

A master hydraulic cylinder is shown at 36 and this cylinder is placed in conductive communication with the actuating mechanism 35 by tubing 3?. The latter may include a gauge shown at 38 for indicating the pressure in the line.

Referring now more particularly to Figure 3, a master cylinder 35 is shown as including a main control plunger 38 which is adapted to be affected by a spring 48 the effective tension of which may be adjusted by the screw stem shown at M. The plunger 39 carries a member 42 formed with a recess 43 and on end of a locking lever 44 is received in this recess. The lever 44 is in the shape of a bell crank that is pivotally mounted at 45 on the respective side frame. One arm of the bell crank or lever 44 carries a stub shaft 46 on which is slidably mounted a disc 41. The peripheral edge of the latter meshes with screw thread convolutions 48 which are formed on the end of the shaft 28. It is evident that just so long as the disc 41 engages the convolutions 48 the bell crank 44 will hold the plunger outwardly against the influence of the spring 46. However, when the disc t? rides off the convolution 48, which will occur aftera predetermined number of revolutions of the shaft 28, the spring 40 is rendered effective to bear against the plunger 39 with a predetermined pressure and thus affect the hydraulic system to cause the actuating mechanisms 35 to apply the brakes.

The end of the shaft remote from the convolutions 48 may be provided with a handle 49 which may be employed in setting the device by taking up the disc 41 a required number of turns on the convolutions 48.

While the mode of operation of the above described mechanism is believed to be obvious, it may be briefly outlined by noting that the stem 4| is first adjusted to set up the required tension 4 of the spring 4!]. It is the tension of this sprin which determines the hydraulic pressure which is applied to the brake shoes 33. The disc 47 will also be taken up a required number of turns on the convolutions 48. The number of these turns determines the interval during which the drum will rotate free of brake application. The trolley I6 is retracted to the position adjacent to the upright 10 and the contact loop H is held in the frame I 8 by the clips I9.

As the plane A comes in the hook 25 engages the contact loop if and starts to pull the trolley it along the guide I 5. This exerts a pull on the line 2!. Due to the properties of this line which are present because of the line bein made from nylon or equivalent synthetic plastic fibers a large portion of the initial shock is absorbed in the line itself. However, the pull on the line also causes a rapid acceleration of rotation of the drum 21. As the drum first rotates the brakes are not applied because the bell crank 44 holds the plunger 39 outwardly in non-applying position. After the drum 2! has rotated a predetermined number of revolutions, the disc 4'! rides off the convolutions 48 thereby permittin the spring 48 to urge the plunger 39 inwardly into brake applying position. The hydraulic pressure is now rendered effective in the actuating mechanisms 35 and the brake shoes 33 are urged against the braking surfaces 32 so as to resist rotation of the drum 2?. This brings the aircraft to a stop within the predetermined distance.

While a preferred specific embodiment of the invention is hereinbefore set forth it is to be clearly understood that the invention is not to be limited to the exact construction illustrated and described because various modifications of these details may be provided in putting the invention into practice within the purview of the appended claims.

What is claimed is:

1. In an aircraft landing system, an arresting unit comprising a shaft, a drum drivably mounted on said shaft, a line on said drum, braking devices associated with said drum, a hydraulic system for operating said braking devices and including a main control tank, a threaded sleeve on said shaft, and means meshing with said threaded sleeve and operatively associated with said control tank to render said hydraulic system effective after a predetermined number of revolutions of said shaft.

2. In an aircraft landing system, an arresting unit comprising a shaft, a drum drivably mounted on said shaft, a line on said drum, braking devices associated with said drum, a hydraulic system for operating said braking devices and including a main control tank, means to vary the effective hy draulic pressure of said control tank whereby the brake applying force is adjusted, and mechanism operatively associated with said shaft and tank, whereby said hydraulic system is rendered effective after a predetermined numb-er of revolutions of said shaft.

3. In an aircraft landing system, an arresting unit comprising a shaft, a drum drivably mounted on said shaft, a line on said drum, braking devices associated with aid drum, a hydraulic system for operating said braking devices and including a main control tank, a threaded sleeve drivably carried by said shaft, a disc meshing with the threads of said leeve, a bell crank carrying said disc, and mechanism associated with said bell crank and control tank whereby a change in position of said bell crank renders said hydraulic system effective to apply said brakes.

4. In an aircraft landing system, an arresting unit comprising a shaft, a drum drivably mounted on said shaft, a line on said drum, braking devices associated with said drum, a hydraulic system for operating said braking devices and including a main control tank, a plunger projecting from said control tank, a spring means normally urging said plunger into a retracted position within said tank, a bell crank having one end in interlocking arrangement with said plunger, and mechanism operatively associated with said shaft and bell crank for breaking the interlock between said bell crank and plunger after a predetermined number of revolutions of said shaft.

5. In an aircraft landing system, an arresting unit comprising a shaft, a drum drivably mounted on said shaft, a. line on said drum, braking devices associated with said drum, a hydraulic system for operating said braking devices and including a main control tank, a .plunger partially received within said tank, said plunger having a portion exteriorly of said tank formed with a recess, a spring normally urging said plunger into said tank, mean for adjusting the tension of said spring, a bell crank having one end received in said recess, a disc rotatively carried by said bell crank, and a sleeve drivably carried by said shaft and having threads receiving the edge of said disc.

6. In an aircraft landing system, an arresting unit comprising a drum, a rotatable shaft for mounting said drum extending beyond an end of the drum, means on said extended shaft end, a line on said drum connected to an aircraft, braking devices operatlvely, associated with a surface of said drum, a hydraulic system controlling the operation of the said braking devices, a plunger for actuating the braking devices, control means for said system engageable and disengageable with said first means after a predetermined number of drum revolutions, and resilient means normally held under tension by said system control means for imparting power to the plunger upon disengagement of said system control means with the said first means, to thereby release the tension of said resilient means and impart movement to the plunger to apply the braking devices.

TAYLOR M. BOYER. CLARENCE R. GOTT-S'CHAIL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,359,993 House Nov. 23, 1920 1,789,653 Hoyt Jan. 20, 1931 2,373,413 Plummer Apr. 10, 1945 FOREIGN PATENTS Number Country Date 287,198 Great Britain Mar. 12, 1928 

